<template>
  <div class="count">
      <h1>当前求和sum为：{{sum}}</h1>
      <select v-model.number="num">
          <option value="1">1</option>
          <option value="2">2</option>
          <option value="3">3</option>
      </select>
      <button @click="increment">+</button>
      <button @click="decrement">-</button>
      <button @click="incrementOdd">当前求和为奇数再+</button>
      <button @click="incrementWait">等3s后再+</button>
  </div>
</template>

<script>
export default {
    name:'Count',
    data() {
        return {
            num:1,
            sum:0
        }
    },
    methods: {
        increment(){
            this.sum += this.num
        },
        decrement(){
            this.sum -= this.num
        },
        incrementOdd(){
            if(this.sum % 2)
                this.sum += this.num
        },
        incrementWait(){
            setTimeout(()=>{
                this.sum += this.num
            },300)
        }

    },
}
</script>

<style>

</style>